Track effects in the radiolysis of aromatic liquids

The chemical effects induced by the track structure of heavy ions have been exploited to show that H-2 production in the radiolysis of simple aromatic liquids (benzene, pyridine, toluene and aniline) is primarily due to second order processes. Similar dependences of H-2 yields on the linear energy transfer, LET, for each of these compounds suggest a common mechanism for H-2 formation. Furthermore, the yields of H-2 are significant at very high LET and they approach that found with aliphatic compounds. Yields of "dimers" (biphenyl, bibenzyl, dipyridyl, and diphenylamine for benzene, toluene, pyridine, and aniline, respectively) have different dependences on LET reflecting the variety of pathways leading to their production. Bibenzyl formation in toluene exhibits a complex dependence on LET suggesting several competing pathways for its production whereas biphenyl formation in benzene is nearly independent of LET suggesting a unimolecular process. Dipyridyl, and diphenylamine yields in pyridine and aniline, respectively, decrease with increasing LET, which indicates that their precursor is being depleted. (C) 2011 Elsevier Ltd. All rights reserved.